STATE HOUSE — An attempt to make it easier for veterans to access medical marijuana could actually cement a registration process that imposes roadblocks for other patients, according to advocates.

Last month, the Senate tacked on to its fiscal 2017 budget a medical marijuana registration fee waiver for veterans who qualify as patients under the state’s dispensary program.

On Monday, the Massachusetts Patient Advocacy Alliance — backers of the 2012 ballot question that legalized medical marijuana in the state — announced its opposition to the amendment, which they argued would “enshrine” a fee that runs contrary to the medical marijuana law’s original intent.

Joining the alliance in speaking against the veteran’s fee waiver was Stephen Mandile, an Army veteran and medical marijuana advocate whose meeting with Sen. Jason Lewis prompted the lawmaker to file the amendment.

“I’m clearly against it now if it’s going to affect every other patient,” Mandile told the News Service.

The medical marijuana law allows registered patients to possess up to a 60-day supply of marijuana for medical use if they are diagnosed with “cancer, glaucoma, positive status for human immunodeficiency virus, acquired immune deficiency syndrome (AIDS), hepatitis C, amyotrophic lateral sclerosis (ALS), Crohn’s disease, Parkinson’s disease, multiple sclerosis and other conditions as determined in writing by a qualifying patient’s physician.”

Qualifying patients must pay $50 to register for the program, and renew their registration with a $50 payment each year. The fee can be waived for people who submit proof of “verified financial hardships,” including MassHealth members and people whose household income is below 300 percent of the federal poverty level.

The Massachusetts Patient Advocacy Alliance argues its members never intended to see patient registration fees charged, and that codifying a fee waiver for one group of patients — veterans — would write the fee itself into law and “substantially change” the policy voters approved in 2012.

“The fees were only ever meant for the dispensaries so that this program would be revenue-neutral,” Nichole Snow, the alliance’s executive director, said. “The costs were never meant to be on the backs of the patients.”

At a media availability outside the State House Monday, patients who qualified under the medical marijuana program stood with the alliance to tell stories of hurdles they’ve faced in paying the registration fee or proving their eligibility hardship waivers.

As of May 31, there were 25,980 active patients in the medical use of marijuana program and six dispensaries open, according to the Department of Public Health.

“Myself and no veteran in Massachusetts wants to make anything harder for anybody else looking to get healing as well from medical cannabis,” said Mandile, the founder of an organization called Veterans Alternative Healing. “We were very disappointed that this first step has become a problem, and we will not stop looking for future ways to make things more accessible.”

The medical marijuana fee waiver is one of several policy riders whose fate will be determined by a conference committee of six legislators reconciling the competing House and Senate budgets for the fiscal year that begins on Friday.

The Massachusetts Patient Advocacy Alliance and Veterans Alternative Healing say they are urging the committee to leave the waiver out of the final compromise budget.